_Aptornis defossor_ Owen, Trans. Zool. Soc. VII, pp. 353 to 366, pls.
40-44 (1871).
The skull differs from that of _A. otidiformis_ by the vertical surface of
the descending part of the occiput being less deeply concave, the occipital
foramen relatively smaller. The hind part of the base of the alisphenoid is
more produced and tuberous outside the end of the hyoid process of the
paroccipital in _A. defossor_.